I use one of these
SPC Performance 91000 SPC Performance FasTrax Camber Caster Gauges | Summit Racing
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I have a set of toe plates and a a used set of old Hunter turn plates that I got pretty cheaply, they're out of a professional alignment shop and weigh a ton. But there are lots of cheap turn plates available now too, they don't have to be fancy. You can also just use a teflon sheet and some dish soap, the wheels just have to turn smoothly.
As far as the alignment shop most of them are totally useless nowadays for these cars. If they'll do the alignment at all most insist on using factory specs because that's what's in the their computer, but those specs are totally wrong for radial tires. And if you have aftermarket suspension parts a lot of shops won't touch the car at all unless they did the install.
It takes a little practice to get accurate, repeatable results at home, but it's time well spent and it's really not that hard. Just a little bit of a learning curve with the equipment. Once you get past that, you'll be better than the kids at the alignment shop will give you anyway. "Alignment tech" is about one half step above "oil change tech" in terms of mechanical skill, and most places won't let the "oil change techs" even remove the drain plug anymore, so that tells you their skill level. Most "alignment techs" have no concept of suspension geometry, they just twiddle the adjustments until the computer turns the box green. Which is why it's a waste of time to try and tell them that the factory specs are for bias ply tires and are actually completely backward for radials, and that sending one of these cars out with radial tires and the alignment set to factory specs is in fact far worse than using the SKOSH chart. But they don't know enough about tire construction or suspension geometry to understand that.
